Cushion

ABSTRACT

A packing cushion of foamed plastic material comprising a flat cushion portion and at least one standing portion, the standing portion being formed from a part of one edge of the flat portion by non-parallel, spaced apart slits cut through the thickness of the flat portion adjacent one of its edges and a third slit cut part way through the thickness of the flat portion to form a hinge whereby when the standing portion is bent at a 90* angle to the flat portion the edges of the standing portion engage with the edges of the flat portions along the non-parallel, spaced apart slits to hold the standing portion in a perpendicular position with respect to the flat portion.

United States Patent [191 Hanaue Dec. 17, 1974 [21] Appl. No.: 359,317

[30] Foreign Application Priority Data May 24, 1972 Japan 47-60773 [52] US. Cl 229/14 C, 46/26, 52/610, 217/53, 206/523, 220/31 S [51] Int. Cl B65d 81/04, B65d 85/30 [58] Field of Search 206/523, 521; 217/53, 52, 217/35; 229/14 C, DIG. 1, DlG. 8; 220/315; 52/610; 46/25, 26

3,580,469 5/1971 Reese 206/523 3,613,985 10/1971 Goodsite 229/DIG. 1

3,655,112 4/1972 Jeffers 229/D1G. 1 3,695,421 10/1972 Wood 206/523 Primary ExaminerWi1liam T. Dixson, Jr. Attorney, Agent, or Firm-Lewis H. Eslinger; Alvin Sinderbrand [5 7 ABSTRACT A packing cushion of foamed plastic material comprising a flat cushion portion and at least one standing portion, the standing portion being formed from a part of one edge of the flat portion by non-parallel, spaced apart slits cut through the thickness of the flat portion adjacent one of its edges and a third slit cut part way through the thickness of the flat portion to form a hinge whereby when the standing portion is bent at a 90 angle to the flat portion the edgesof the'standing portion engage with the edges of the flat portions along the non-parallel, spaced apart slits to hold the standing portion in a perpendicular position with respect to the flat portion.

15 Claims, 22 Drawing Figures PATENTEL SEE I 71974 SHEH 5 BF 6 PATENTEB DEC] 7 I974 sum 5 or 6 CUSHION BACKGROUND OF THE INVENTION This invention relates to packing cushions for use with rigid enclosures and more particularly to plastic cushions for use in packing cartons.

One prior art type of foamed plastic packing cushion is pre-pressed into a generally rectangular, hollow box shaped (FIG. 1 Another prior art type of foamed plastic packing cushion is made from separate parts of flat foamed plastic material which are glued together to. form a suitable, generally rectangular shape (FIG. 2). A disadvantage of such prior art packing cushions is that because they are pre-formed prior to the packing operation they are relatively bulky, require a great deal of storage space, and are difficult to stack. Even if the prior art embodiment illustrated in FIG. 2 is constructed of its separate parts during the packing operation a great deal of time is thereby wasted.

SUMMARY OF THE INVENTION The above and other disadvantages are overcome by the present invention of a foldable packing cushion comprising a flat part and a standing part made of resilient material of substantial thickness, the standing part being hinged to the flat part. At least one of the standing and flat parts has a projecting, generally trapezoidal shaped tab which engages within a similarly shaped recess in the other of the standing and flat parts prior to being folded. The standing and flat parts each have a set of corresponding, orthogonally related edges which are initially compressed and then engaged with each other when the standing part is bent substantially perpendicular with the flat part during folding whereby the engagement of the corresponding edges maintains the perpendicular relationship of the flat and standing parts after being folded.

In the preferred embodiments the tab is formed by a pair of non-parallel, spaced apart first and second slits cut through the thickness of either the flat part or the standing part and a third slit which is generally parallel to one edge of the flat part and which extends partially through the thickness of the flat part to define a hinge for the standing part. The standing part is then maintained in a position substantially perpendicular to the fiat part by the engagement of the top surface edges of the tab along the first and second slits with the edges of the surface of the opposite part which are exposed by the third slit when the standing part is bent at an angle of substantially 90 to the flat part.

. In the preferred embodiments the cushioning material is made of foamed plastic. In some embodiments a plurality of standing parts are formed at different sides of the flat part by interior three sided slits, two sides of which are diverging with respect to each other from the partial slit which defines the hinge portion. In still other embodiments separate standing parts are similarly formed from other standing parts.

In still another embodiment one or more packing cushions of the type described above are incorporated along the folding lines of a folded container, such as a cardboard packing container, such that the-standing and flat portions are formed in the manner described above simultaneously with the folding of the carton.

It is therefore an object of the present invention to provide a lightweight packing cushion having a flat porv It is still another object of the present invention to provide a packing cushion for use with a folding carton wherein the packing cushion has flat and upright portions which are interengageable with each other to maintain their relative positions.

The foregoing and other objectives, features,and advantages of the invention will be more readily understood upon consideration of the following detailed description of certain preferred embodiments of the invention, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, partly in section of a prior art packing cushion of the type which is preformed by stamping or molding;

FIG. 2 is a perspective view, partly in section, of a prior artpacking cushion pre-formed of separate elements;

FIG. 3 is a plan viewof a packing cushion according to one embodiment of the invention prior to being forrnedinto upright and flat portions;

FIG. 4 is a sectional view taken generally along the line IVIV in FIG. 3;

FIG. 5 is a sectional view taken generally along the line VV in FIG. 3;

FIG. 6 is a perspective view of the embodiment of FIG. 3 after the standing portion has been folded into an upright position;

FIG. 7 is a plan view of the embodiment of FIG. 6;

FIG. 8 is a sectional view taken generally along the line VIIlVlII in FIG. 7 and'including a suitable container and article with which the cushion is to be used;

FIG. 9 is a sectional view taken generally along the line IX-IX in FIG. 7;

FIG. 10 is a plan view of a flat cushion according to a second embodiment of the invention prior to being folded into upright and flat portions;

FIG. 11 is a sectional view taken generally along the line XIXI in FIG. 10;

FIG. 12 is a sectional view taken generally along the line XII-XII in FIG. 10;

FIG. 13 is a perspective view of the embodiment of FIG. 10' illustrating the bending of the standing portions into an upright position;

FIG. 14 is a perspective view of the embodiment of FIG. 10 when the standing portions have been folded into their completed, upright positions;

FIG. 15 is an inverted, perspective, bottom view of a selected comer of the embodiment of FIG. 13;

FIG. 16 is a plan view of a flat cushion of a third embodiment of the invention prior to being folded into flat and standing portions;

FIG. 17 is a perspective view of the embodiment of FIG. 16 as it is being bent into its final shape;

FIG. 18 is a perspective view of the completed cushion of the embodiment depicted in FIG. 16;

FIG. 19 is a perspective view of a pair of cushions of the embodiment of FIG. 16 as installed in a cardboard carton to protect an article within the carton;

FIG. 20 is a perspective view of a carton with a fourth embodiment of the invention;

FIG. 21 is a perspective view of a portion of the carton depicted in FIG. 20 illustrating the forming of the cushion of the invention; and

FIG. 22 is a perspective view of the completed carton of the embodiment of FIG. 20.

DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS With reference now to FIG. 1 a prior art packing cushion of one type is illustrated. Typically the cushion 1 is formed by a press so as to provide a hollow portion in which a suitable article is placed. With reference to FIG. 2 a prior art cushion of a second type is illustrated. With this type of packing cushion 2 there are provided a plurality of block members 2a, 2b, 2c and 2d which are adhered together by an adhesive 3 to form a shape substantially similar to the shape of the cushion of FIG. 1. In both types of these embodiments the cushions are typically formed in their generally rectangular shape with the hollow portion prior to the packing operation. Thus these packing cushions require an unnecessary amount of storage space. Furthermore, in regard to the second type of packing cushion, time is wasted in its construction because of the necessity of separately forming the parts of the cushion.

These disadvantages are overcome by the present invention as illustrated in FIG. 3. A cushion is made of foamed and inflated beads of plastic material, for example, such as polyethylene. The cushion 10 is initially constructed as a flat portion 11. This flat portion is easily stored and stacked prior to the packing operation.

A pair of spaced-apart, non-parallel slits 13 are cut or punched through the thickness L of the flat portion 11 to extend frome one of the side edges 11a of the flat portion 11 into the flat portion 11 in diverging directions. As is more clearly shown in FIG. 5, the slits 13 extend from a top surface 11d to a bottom surface 11b of the flat portion 11. A third slit 15 is cut or punched partially through the thickness L of the flat portion 11 to form a hinge 14. With reference to FIG. 4, the slit 15 extends from the bottom surface 11b a predetermined distance toward the top surface 11d, leaving a hinge portion 110. Together the slits 13 and 15 define a trapezoidal shaped standing portion 12. The slit 15 runs in a direction generally parallel to the side edge 11a but in other embodiments it may take a different direction.

The side edges of the flat portion 11 along its top surface lld located at the beginning of the slit 13 are designated 13b. The edges of the standing portion 12 exposed by the hinge slit 15 and located along the entrance to the slit 13 are designated 13a. As is more clearly illustrated in FIG. 6, when the standing portion 12 is bent upwardly, as viewed in FIGS. 3 and 6, at an angle of substantially 90 to the upper surface 11d the edges 13a and 13b are initially compressed and then expanded to engage each other and hold the standing por tion 12 in its perpendicular position with respect to the flat portion 11.

If the cushion 10 is next placed within a carton E (FIG. 8) a suitable article T, for example a magnetic tape recorder, phonograph, radio receiver, television set or audio equipment may be placed on the cushion 10 such that it is cushioned against the bottom of the carton and at least one side wall of the carton E.

Referring now more particularly to FIG. 10 a second embodiment of the invention is illustrated. A cushion 20 made of foamed plastic material is comprised of a flat portion 21 having segmented side portions 22a, 22b, 22c and 22d. The side portions are segmented from the main portion 21 by slits 29 between the various side portions. A slit 26 cut through the thickness of the side portion 22a running in a direction generally parallel to the edge of the side portion 22a but spaced from it connects with a pair of spaced apart slits 26a and 26b. The slits 26a and 26b are also cut through the thicknesses of the side portion 22a and the flat portion 21. The slits 26a and 26b are directed in diverging directions away from the slit 26.

A slit 27 cut part-way through the thickness of the flat portion 21 and running generally parallel to the slit 26 joins the ends of the slits 26a and 26b. Since the slit 27 only extends partly through the thickness of the flat portion 21 it defines a hinge portion 28 (FIG. 11). Together the slits 26, 26a, 26b and 27 define a portion 23 which, as will be explained in greater detail hereinafter, constitutes a standing portion.

The side portion 22b is opposite the side portion 22d and the side portion 22c is perpendicular to both and extends between their corresponding ends. These side portions are substantially identical in construction so that the same reference numerals are used to describe their construction. A slit 30 extending partially through the thickness of the flat portion 21 and running generally parallel to the outside edge of the portion 22b defines a hinge portion 31 (FIG. 12). The slit 30 does not extend the entire length of the side portion 22b but instead is terminated at the ends of a pair of spaced-apart slits 32a and 32b which extend in a direction away from the long edge of the side portion 22b in diverging directions and away from the slit 30 a predetermined distance. The slits 32a and 32b are cut completely through the thickness of the flat portion 21.

The ends of the slits 32a and 32b most distant from the slit 30 are joined together by a slit 33, cut through the thickness of the flat portion 21, which runs generally parallel to the slit 30. Together the slits 32a, 33 and 32b define a trapezoidal tab portion 38 of the side portion 22b which is cut from the flat portion 21'. As will beexplained in greater detail hereinafter this tab portion forms a set of locking edges with the edges of the corresponding cut-out area 39 (FIGS. 13-15) of the flat portion 21 exposed by the hinge slit 30 to hold the side portion 22b in an upright position. v

In a similar manner the side portions 220 and 22d likewise have .interconnecting slits 30, 32a, 33 and 32b which form hinge and tab portions 31 and 38, respectively, and which have therefore been designated with the same corresponding reference numerals.

. The side portion 22a is hinged to the flat portion 21 by a hinge portion 34 formed by a slit 35 which extends partially through the thickness of the flat portion 21 but not through the standing portion 23. The flat portion 21 is provided with a plurality of finger grip holes 25 for removing the cushion from the packing box. In some embodiments the manufacturers name 24 is punched out of the flat portion 21 in such a manner that it will read correctly from the reverse side as illustrated in FIG. 10.

Referring now more particularly to FIGS. 13-15 the manner of assembling the packing cushion of the second embodiment is illustrated. The standing portion 23 is first folded upwardly along the hinge 28 and is held in its upright position by the engagement of the edges of the surface of the portion 23 exposed by the hinge slit 27 and located along the slits 26a and 26b with the top surface edges of the flat portion 21 along the slits 26a and 26b (in the vicinity of the hinge 34) in a manner similar to that described with reference to the first embodiment. The individual standing portion 23 serves as a spacer. I

The side portions 22b, 22c and 22d are next folded into upright positions and are held in these upright (perpendicular) positions by the edges of the tabs38 defined by the slits 32a, 33 and 32b as will be explained in more detail hereinafter. The side portion 22a of this embodiment is not held in an upright position except by the enclosure in which the cushion is inserted.

Referring now more particularly to FIG. an inverted bottom view of the corner A at the intersection of the side portions 220 and 22d as viewed in FIG. 14 is depicted. The intersection of the slits 32b and 33 in the side portion 22c define an edge 36 at the top surface of the side portion 220 which engages with an edge 37 of the surface of the flat portion 21 exposed by the hinge slit along the intersection of the slits 32b and 30. Similar engaging edges at the intersection of the slits 32a, 30 and 33 also help to'hold the side portion 220 in an upright position. Likewise with respect to the side portions 22b and 22d the slits which define the tab portions 38 form inter-engaging edges 36 and 37 which hold them in perpendicular positions to the flat portion 21.

Referring now more particularly to FIG. 16 a third embodiment of the invention is illustrated as comprising a packing cushion 40 having a relatively flat portion 41 and two opposed side portions 42 and 43. As in the other embodiments described above the side portions 42 and 43 are adapted to be folded upwardly and perpendicular to the flat portion 41 in the manner to be described. The side portions 42 and 43 are substantially identical in construction and therefore only one of the side portions will be described and the same reference numerals will be applied to identical parts in the drawings. The side portion 42 is hinged to the flat portion 41 along a line 44 which is produced by slits 45 which tions at lines 52. The hinge lines 52 are formed by partial slits 53 in the thicknesses of the-side portions 42 and 43. A pair of spaced-apart slits 54 which extend into each end side portion 51 from the hinge line 52 in a diverging manner together with a slit 55 joining the extreme ends of the slits 54 form a trapezoidal tab 56 at each end of the side portions 42 and 43.

As is illustrated more clearly in FIGS. 17 and 18 the side portions 42 and 43 are folded upwardly as the end portions 51 are folded inwardly. When all of the hinged portions are folded at 90 with respect to their opposite hinge portions a rectangular, hollow box is formed as is illustrated in FIG. 18. In the manner of the previously described embodiments the edges of the trapezoidal tab portions formed by the slits engage with the exposed edges of the cut-out portions to hold the .side

portions in their perpendicular positions. The rectangular box cushion formed in FIG. 18 is fitted over each end of an article T to be shipped in a container E as is illustrated in FIG. 19 to suspend and cushion the article T from the sides of the box E. The tab portions 49 act as spacers against the box E. In still other embodiments the tab portions 49 are formed to be of the same shape as the tab portions 46 to give additional'support to hold the side portions 42 and 43 in their upright positions.

Referring now more particularly to FIG. 20 still another embodiment of the invention isillustrated for use with a folding carton. In the embodiment of FIG. 20 a 102 and 103 hinged at opposite sides of the bottom extend partly through the thickness of the flat portion 41 as in the above described embodiments.

The hinge 44 is interrupted by two spaced-apart trapezoidal tab portions 46 each of which is partially defined by a pair of spaced-apart slits 47 cut through the thickness of the flat portion 41 and which diverge away from the hinge line 44. The ends of the spaced-apart slits 47 furthest away from the hinge line 44 are joined by a slit 48 cut through the thickness of the flat portion 41 which runs generally parallelto the hinge line 44. In between the tab portions 46 is a tab portion 49 formed of the flat portion 41 and defined by a trapezoidal slit 50 in the side portion 42 whose non-parallel sides converge from the hinge line 44 and extend into the side portion 42. v At each end of .the side portions 42 and 43 are additional end portions 51 which are hinged to the side porportion 101. Two additional folding side portions 104 and 105 are hinged at the remaining opposite sides of the flat portion 101. Each of the side portions 102 and 103 additionally has a portion 106 and 107, respectively, hinged from it to form' a top to the box. The side portions 102, 103, 104 and 105 are joined together by webs 108 for structural rigidity. The webs 108 fold inwardly to secure the article to be enclosed by the box.

With respect to the teachings of the present invention a flat portion of cushioning material 110 is fastened to the bottom portion 101 at the ends to which the side portions 104 and 105 are hinged. Each of the flat cushions 110 has side portions 111 hinged to it by partial slits in the manner described above with reference to the previous embodiments such that there are provided interlocking trapezoidal tabs 112 to hold the side portions in a perpendicular fashion with respect to the flat portion 110. The side portions 111 are not rigidly affixed to the side portions 102, 103, 104'and 105 and are thus able toslide with the side portions of the carton 100 when they are-folded upwardly 'to form the rectangular box. In forming the box 100 the cushions 110 and the side portions 111 are maintained in their perpendicular positions by the arrangement of trapezoidal tabs and slits described above with reference to the other embodiments.

It should be apparent that the teachings of the present invention may be applied to a number of other embodiments, however, all such embodiments contain certain elements in common. These elements are that there is provided a flat sheet of cushioning material and that at least one side portion is formed from the sheet by a trapezoidal arrangement of slits extending completely through the thickness of the sheet and by a line of one or more partially cut-through slits which form a hinge section.

The slits which extend completely through the sheet (cut-through slits) are designed in such a manner that they define a trapezoidal tab. The tab, when bent perpendicular to the portion from which it is cut by the slits is held in its perpendicular position by the interengagement of one set of edges, which are either on a top surface of the tab or the surface of the tab which is exposed by the hinge slit with another set of edges located on the portion from which the tab is cut along its surface as exposed by the hinge slit or on its top surface, respectively, adjacent the cut-through slits.

In some embodiments the non-parallel slits extend from the hinge line either into the flat portion or into the side portion in a direction such that they diverge from the hinge line and are joined by a cut-through slit running generally parallel to the hinge line. Thus in some embodiments the interlocking tabs formed by tionship by trapezoid shaped tabs formed by slits in the side portions which diverge outwardly from a hinge line formed by a partial slit in the side portion.

The terms trapezoid" and trapezoidal have been used generally herein to refer to a four sided geometric shape, two of whose sides are non-parallel. The trapezoid shape of the tabs is defined in most of the embodi ments by the arrangement of the slits on three sides and by a projection of the hinge line or by the side edge on the fourth side. In all of the above described embodiments the non-parallel sides are substantially of the same length and make equal and opposite angles with the hinge line, however, in other less advantageous embodiments of the invention the non-parallel sides are not of equal length and do not necessarily make equal and opposite angles with the hinge line. For the purposes of the invention it is only necessary that the slits cut a tab shaped such that when bent perpendicularly with the portion from which it is cut, it will be supported in the perpendicular position by the engagement of the orthogonally related sets of edges referred to above.

The terms flat and standing used to describe the various portions are, of course, relative and merely used to aid in the description. Thus, with reference to the embodiment of FIGS. 16-19, for example, the portions'51 may be said to be standing" with respect to the flat portions 42 and 43 to which they are hinged.

The composition of the cushion material has been described above as being made of foamed plastic but it will be understood that in other embodiments other forms of soft resilient material, such as corrugated paper for example, may be utilized, provided the sheet of cushion material has a thickness substantial enough to create the orthogonally related edges.

The standing portions of the above embodiments are all described as being hinged to the flat portions by partial slits. This construction has the advantage of simplicity and economy but in other less advantageous embodiments the standing portions may be separately formed and hinged by a web member or the like to the flat portion. Such embodiments still have the advantages that they may be easily stored and easily folded for packing. In general it is only necessary that the foldable cushion of the invention comprise a flat part and a standing part made of resilient material of substantial thickness, the standing part being hinged to the flat part and at least one of the standing and flat parts having a projecting, generally trapezoidal shaped-tab which engages within a similarly shaped recess in the other of the standing and flat parts prior to being folded. The

standing and flat parts each must have a set of corresponding, orthogonally related edges which are initially compressed and then engaged with each other when the standing part is bent substantially perpendicular with the flat part during folding whereby the engagement of the corresponding edges maintains the perpendicular relationship of the flat and standing parts after being folded.

The terms and expressions which have been employed here are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions, of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. A foldable packing cushion comprising a flat part and at least a first standing part of resilient material, the standing part being hinged to the flat part, atleast one of the standing and flat parts having a projecting, generally trapezoidal shaped tab which engages within a similarly shaped recess in the other of the standing and flat parts prior to being folded, the standing and flat parts each having a set of corresponding, orthogonally substantially perpendicular with the flat part during folding whereby the engagement of the corresponding edges maintains the perpendicular relationship of the flat and standing parts after being folded.

2. A foldable packing cushion as recited in claim 1 wherein the standing part is formed from the flat part by at least one hinge slit cut partially through the thickness of the flat part, thereby dividing the two parts and making a hinge of a portion of the resilient material, the trapezoidal shaped tab is at least partially formed by two spaced apart, non-parallel slits cut through the thickness of the one of the flat and standing parts, and at least one of the non-parallel slits joins the hinge slit.

3. A foldable packing cushion as recited in'claim 2 wherein the trapezoidal shaped tab is also partially formed by a slit cut through the thickness of the one of the flat and the standing parts and which joins the spaced apart slits at their ends opposite the hinge slit.

4. A foldable packing cushion as recited in claim 3 wherein the slit joining the ends of the spaced apart slits opposite the hinge slit is oriented in a direction substantially parallel to the hinge slit.

5. A foldablepacking cushion as recited in claim 3 wherein the spaced apart slits diverge from each other in the direction away from the hinge slit and toward the slit joining their opposite ends.

6. A foldable packing cushion as recited in claim 3 further comprising at least a second standing part hinged to the first standing part.

7. A foldable packing cushion as recited in claim 1 wherein the resilient material has a substantial thickness.

,8. A foldable packing cushion as recitedin claim 7 wherein the cushion material comprises foamed and inflated beads of plastic material.

9. A foldable packing cushion as recited in claim 7 wherein the plastic material is comprised of polyethylene.

10. A foldable packing cushion as recited in claim 1 further comprising a plurality of standing parts substantially similar in construction to the first standing part and hinged in substantially the same manner as the first standing part to the flat part.

11. A foldable packing cushion comprised of a sheet of resilient material having a substantial thickness, the sheet being divided into a flat part and a standing part by a partial slit through the thickness of the sheet which forms a hinge between the flat and standing parts, one of the flat and standing parts having a projecting tab which interrupts the partial slit and which is cut from the other of the flat and standing parts by a trapezoidal arrangement of slits cut through the thickness of the other of the flat and standing parts, at least two of the slits being spaced from each other, non-parallel with respect to each other, and non-perpendicular and nonparallel to the partial slit, the slits defining a set of normally orthogonal edges on the flat and standing parts which become inter-engaged to support the standing part when it is bent substantially perpendicular to the flat part and to maintain the perpendicular relationship between the flat and standing parts.

12. A foldable packing cushion as recited in claim 11 wherein the spaced apart slits extend in diverging directions away from the partial slit and are joined at their ends most distant from the partial slit by an additional slit cut through the thickness of the other of the flat and standing parts.

13. A foldable packing cushion as recited in claim 12 wherein the additional slit runs in a longitudinal direction generally parallel to the longitudinal direction of the partial slit.

14. A foldable packing cushion as recited in' claim 11 wherein a plurality of such projecting tabs are thus formed on one of the flat and standing parts.

15. A foldable packing cushion as recited in claim 11 wherein the sheet has bottom and top surfaces, the partial slit extends from the bottom surface toward the top surface, one of the sets of inter-engageable edges is located on the top surface of the projecting tab, and the other set of interengageable edges is located on a surface exposed by the partial slit on the other of the flat and standing parts. 

1. A foldable packing cushion comprising a flat part and at least a first standing part of resilient material, the standing part being hinged to the flat part, at least one of the standing and flat parts having a projecting, generally trapezoidal shaped tab which engages within a similarly shaped recess in the other of the standing and flat parts prior to being folded, the standing and flat parts each having a set of corresponding, orthogonally related edges which are initially compressed and then engaged with each other when the standing part is bent substantially perpendicular with the flat part during folding whereby the engagement of the corresponding edges maintains the perpendicular relationship of the flat and standing parts after being foldEd.
 2. A foldable packing cushion as recited in claim 1 wherein the standing part is formed from the flat part by at least one hinge slit cut partially through the thickness of the flat part, thereby dividing the two parts and making a hinge of a portion of the resilient material, the trapezoidal shaped tab is at least partially formed by two spaced apart, non-parallel slits cut through the thickness of the one of the flat and standing parts, and at least one of the non-parallel slits joins the hinge slit.
 3. A foldable packing cushion as recited in claim 2 wherein the trapezoidal shaped tab is also partially formed by a slit cut through the thickness of the one of the flat and the standing parts and which joins the spaced apart slits at their ends opposite the hinge slit.
 4. A foldable packing cushion as recited in claim 3 wherein the slit joining the ends of the spaced apart slits opposite the hinge slit is oriented in a direction substantially parallel to the hinge slit.
 5. A foldable packing cushion as recited in claim 3 wherein the spaced apart slits diverge from each other in the direction away from the hinge slit and toward the slit joining their opposite ends.
 6. A foldable packing cushion as recited in claim 3 further comprising at least a second standing part hinged to the first standing part.
 7. A foldable packing cushion as recited in claim 1 wherein the resilient material has a substantial thickness.
 8. A foldable packing cushion as recited in claim 7 wherein the cushion material comprises foamed and inflated beads of plastic material.
 9. A foldable packing cushion as recited in claim 7 wherein the plastic material is comprised of polyethylene.
 10. A foldable packing cushion as recited in claim 1 further comprising a plurality of standing parts substantially similar in construction to the first standing part and hinged in substantially the same manner as the first standing part to the flat part.
 11. A foldable packing cushion comprised of a sheet of resilient material having a substantial thickness, the sheet being divided into a flat part and a standing part by a partial slit through the thickness of the sheet which forms a hinge between the flat and standing parts, one of the flat and standing parts having a projecting tab which interrupts the partial slit and which is cut from the other of the flat and standing parts by a trapezoidal arrangement of slits cut through the thickness of the other of the flat and standing parts, at least two of the slits being spaced from each other, non-parallel with respect to each other, and non-perpendicular and non-parallel to the partial slit, the slits defining a set of normally orthogonal edges on the flat and standing parts which become inter-engaged to support the standing part when it is bent substantially perpendicular to the flat part and to maintain the perpendicular relationship between the flat and standing parts.
 12. A foldable packing cushion as recited in claim 11 wherein the spaced apart slits extend in diverging directions away from the partial slit and are joined at their ends most distant from the partial slit by an additional slit cut through the thickness of the other of the flat and standing parts.
 13. A foldable packing cushion as recited in claim 12 wherein the additional slit runs in a longitudinal direction generally parallel to the longitudinal direction of the partial slit.
 14. A foldable packing cushion as recited in claim 11 wherein a plurality of such projecting tabs are thus formed on one of the flat and standing parts.
 15. A foldable packing cushion as recited in claim 11 wherein the sheet has bottom and top surfaces, the partial slit extends from the bottom surface toward the top surface, one of the sets of inter-engageable edges is located on the top surface of the projecting tab, and the other set of interengageable edges is located on a surface exposed by the partial slit on the other of the flat and standing parts. 